Transcript O-0003 Prevent and Treat Hot Weather Injuries – PPTX

CAP Ground Team
-
Task O-0003
Prevent & Treat Hot Weather Injuries
Revision January 2012
Prevent & Treat Hot Weather
Injuries(Task O-0003)
Reference:
Ground & Urban Direction Finding Team Tasks (24 May 2004)
Ground Team Member & Leader Reference Text (Revised Arpil 2003)
Objectives
Take steps to prevent hot weather
injuries and recognize and treat those
that do occur.
PROBLEMS DUE TO
HOT WEATHER
• Hot climate degrades physical performance and
places each member of the team at risk for heat
illness.
• The risk of heat illness depends on physical activity,
hydration, heat acclimatization, clothing, load
carried, terrain, and climatic conditions.
• Leaders must watch their team carefully for signs of
distress in the heat and adjust work/rest schedules,
work rates and water consumption according to
conditions.
SWEAT
• In very hot conditions, sweating is the only mechanism
for heat loss.
• Water must be consumed to replace the body's loss of
sweat. If the body water lost through sweating is not
adequately replaced, dehydration will follow.
• Dehydration will lead to heat illness.
• Heat, high humidity and exposure to the sun all tend to
increase body temperature and increase water
requirements, primarily through loss of body water as
sweat.
• Sweat rates can be high even when the skin looks and
feels dry, since sweat evaporates very quickly in dry air.
DEHYDRATION
• Dehydration cancels the benefits of heat acclimatization,
increases the risk of heat illness, reduces work capacity,
appetite, and alertness. The greater the dehydration the more
severe the effects.
• Thirst is a poor indicator of dehydration. Ground team
members in the field do not sense when they are dehydrated
and usually do not replace body water losses, even when
drinking water is readily available.
• Personnel under stress in hot environments will exhibit
"voluntary dehydration". They maintain themselves about 1.5
quarts below their ideal hydration status without any sense of
thirst.
• Ground team members must consciously remind themselves,
or be reminded to replace water lost to sweat.
• Ensuring regular consumption of fluids is the responsibility of
the unit leader.
Your whole body suffers
when your thirsty
How Heat Affects
Performance
• Heat degrades mental performance as well as physical
performance.
• Rested, well-trained team members working on sedentary
tasks should be able to work normally in the heat for up to four
hours, after that mental performance will steadily deteriorate.
• Tasks which require sustained attention (e.g., site security) will
be affected more quickly.
• Performance in the following jobs will be affected by heat
stress: monotonous, repetitive, or boring tasks; tasks which
require attention to detail and short-term memory (e.g.,
calculations, map plotting, passing formal messages, etc.);
tasks which must be done quickly or according to a fixed
schedule; tasks which require arm-hand steadiness;
command and operations tasks where confusion and
misinformation are common.
• Reaction times and decision times are slower in the heat.
“…heat is by far the number one killer of all weather events…”
Courtesy NOAA’s National Weather Service
Heat Stress Prevention
• Heat injuries (sometimes called heat stress) are the
result of overexertion and dehydration.
• These conditions can occur at any time during the
year, but are most common during the summer
months with high temperatures and humidity.
Control of Problems due to
Hot Weather
• The key to preventing heat illness and sustaining
performance is knowledge of the environmental
conditions.
• Leaders must have accurate weather information for
their specific location.
• If members are not fully acclimatized, adequately fed,
rested and hydrated, the amount of cooling and rest
provided during each work period needs to be
increased.
Acclimatization & Physical Fitness
• Attain the best possible physical fitness and heat
acclimatization prior to missions. Physically fit
personnel acclimatize to heat more rapidly than
those less fit.
• Units on alert, or identified for long term missions,
should emphasize their physical training
program and state of heat acclimatization (e.g.,
spend more time exercising in the heat where
possible).
Acclimatization & Physical Fitness
(continued)
• Significant acclimatization to heat can be
attained in 4-5 days. Full heat acclimatization
takes 7-14 days with 2-3 hours per day of
carefully supervised exercise in the heat.
• Increase physical activity each day until full
acclimatization is achieved.
• Acclimatization requires that progressively more
physical activity be performed each day. During
the first two days of heat exposure, light activities
such as recreation activities or short training
missions would be appropriate. Leaders should
gradually increase the intensity of exercise each
day working up to an appropriate physical
training schedule adapted for the environment.
Acclimatization & Physical Fitness
(continued)
• Acclimatization does NOT reduce and may actually
increase water requirements. Heat acclimatization
increases sweating to enhance the evaporative
cooling capacity of the body. Increased sweating
requires additional water consumption. It is
dangerous and inappropriate to try to reduce water
consumption.
• Personnel may have a few days of increased salt
requirements upon initial deployment because sweat
is salty prior to acclimatization. Complete
consumption of rations with use of salt packets is
essential to provide an adequate salt intake. Salt
supplementation is not appropriate unless medically
indicated and supervised by medical personnel.
HYDRATION
• Leaders must understand the critical importance of
maintaining hydration. Almost any contingency of
military operations will interfere with the maintenance
of hydration.
• Establish mandatory drinking schedules which
replace water lost by sweating.
• Plan operations to provide water re-supply points at a
maximum interval of every three hours. One-hour
intervals are more desirable. Carry as much water as
possible when separated from approved sources of
drinking water. Insure members always have at least
one full canteen in reserve; know when and where
water re-supply will be available. Personnel can live
longer without food than without water.
HYDRATION
(continued)
• Minimize voluntary dehydration by making flavored,
cool water accessible in a comfortable place, and
providing enough time to drink and eat. Before
flavoring water, be sure that it is potable. Flavoring in
individual canteens should be avoided; it increases
the risk of contamination and illness.
• Carbohydrate/electrolyte beverages (sports drinks)
are not required, and if used should not be the only
source of liquid.
• Drinking water does more good than splashing it on
the skin. Water splashed on the skin is wasted water;
it might briefly improve comfort, but does little to
sustain performance and avoid heat illness.
Clothing, Equipment & Supplies
• Change socks when they become soaked with sweat.
Prolonged wear of wet socks can lead to foot injury (e.g,
increased risk of blisters).
• Sweat accumulation in the boot can be reduced by wearing a
sock that is absorptive and thick enough to "wick" moisture
away from the foot and toward the top of the boot where
evaporation can occur.
• Find a sock combination that works well for you, but remember
that cotton athletic socks are a no-no.
• Some people find that one pair of synthetic socks works best for
them, some find that two pairs is better, some find that a thin
inner sock and a thick outer sock works. Whatever you choose,
make sure your boots are correctly fitted for you with the socks
you will be wearing.
Clothing, Equipment & Supplies
(continued)
• Uniforms should be worn to protect against sun,
wind and insects. Wear the uniform properly,
blouse trousers and roll down sleeves. Use hats,
head cloths and sunscreen. Heat strain will be
reduced by shielding the body from the sun.
Wearing Hot Weather Battle Dress Uniform
reduces water requirements by limiting heat gain.
• Because clean clothing protects better and
prevents skin rashes, whenever possible, wash
clothing and air-dry or sun-dry if in the field for
extended periods.
Heat Rash
&
Sunburn
• Heat Rash: a skin rash most commonly found on
clothed areas of the body. Heat Rash can impair
body heat loss and degrade performance for many
days after it's disappearance. Heat rash can be
avoided by practicing good hygiene and keeping
skin clean and dry.
• Sunburn impairs body heat loss, degrades
performance and increases the risk of heat
casualties. Sunburn can be avoided by protecting
skin with clothing and sunscreen. Emphasize the
importance of hats and long sleeves.
Preventing Heat Stress
• Drink enough water!
─ Two quarts per day is the absolute minimum on a mild day. On
a hot summer day, drink 6-8 quarts a day or 1 quart an hour.
Frequent sipping is better than trying to drink an entire quart at
one time
• Monitor the color of your urine!
─ It should be almost clear in color. If it is brown or dark yellow,
you are becoming dehydrated
• Wear loose fitting and open clothing
Preventing Heat Stress
(continued)
• Don’t overexert yourself. Know your limits and do
not exceed them. Take frequent breaks
• Avoid sunburn by using sunscreen or keeping your
sleeves down.
• Watch other members of the team for beginning
signs of heat stress. Immediately stop, rest and
drink some waterl Once a person suffers from a
heat injury, he or she will not be back for the rest of
the day
• Use the buddy system -- Assign everyone a
partner to watch for heat stress and to monitor
water intake
SUNSCREEN
• Sunscreen should also be applied at least 30 minutes
before going outdoors.
• A common mistake is applying too little sunscreen, which
can drastically reduce the effective SPF (Sun-Protection
Factor). In addition, sunscreen must be reapplied at least
every two hours when staying outdoors for a prolonged
period of time.
• People with sensitive skin who burn quickly and must spend
a lot of time outdoors should always apply a sunscreen with
an SPF of 30 or more.
• Also, don’t forget to put and keep sunscreen on your ears,
the back of your neck, as well as the tops of your hands
and feet.
Factors used to Assess
Heat Stress Risk
The 3 Factors that we are going to be discussing in
the next few slides are:
• Personal Risk Factors
• Work Factors
• Environmental Factors
Reference: Construction Safety Association of Ontario
http://www.csao.ort/t.tools/t6.news/heat_stress_faq.cfm#factors
PERSONAL RISK FACTORS
• Weight
─ If you are overweight you are less efficient at loosing heat.
• Poor Physical Condition
─ If you are not in good physical condition, your body is less able to
cope with the demands that heat places on your body.
• Previous Heat Illness
─ You are more sensitive to heat if you have experienced a previous
heat-related illness.
• Age
─ As the body ages, its sweat glands become less efficient
PERSONAL RISK FACTORS
(continued)
• Heart Disease or High Blook Pressure
─ In order to pump blood to the skin and cool the body, the heart rate
increases, which causes stress on the heart.
• Recent Illness
─ Illnesses with diarrhea, vomiting or fever increase the risk of dehydration
• Alcohol Consumption
─ Alcohol consumption during the previous 24 hours leads to dehydration
• Medication
─ Certain medications may cause heat intolerance. You should check with
your doctor
• Lack of Acclimatization
─ When exposed to heat, it takes approximately 6-7 days for your body to
adapt
WORK FACTORS
• Clothing and Personal Protective Equipment (PPE)
─ Heat Stress can be caused or aggravated by wearing PPE suites.
Remember that coated and non-woven materials block the
evaporation of sweat, which is needed to cool the skin.
• Workload
─ The body generates more heat during heavy physical work.
Heavy physical work requires special evaluation even at
temperatures a low as 74° to prevent heat disorders. This is
especially true for those who have not acclimatized to the heat.
ENVIRONMENTAL FACTORS
• Let’s first understand that measuring the temperature
is only one factor in what helps us to measure the
“true” temperature as it affects our body.
• The following are two examples which show why we
need more information then just what the
temperature is.
─ Example 1: It is noon and 100°. You are sitting under a shaded tree
with a nice wind blowing and low humidity (amount of moisture in
the air).
─ Example 2: It is noon and 100°. You are walking in the desert with
no wind blowing and high humidity.
• Even though the temperature is the same in both
examples; I bet you could handle Example 1 for a
lot longer then Example 2.
ENVIRONMENTAL FACTORS
(continued)
• Radiant Heat
─ Radiation is the transfer of heat from hot objects through air to the
body. Working around heat sources will increase heat stress.
Additionally, working in direct sunlight can substantially increase
heat stress. You will be far more comfortable working at 93°F under
cloudy skies than working at 93°F under sunny skies.
• Humidity
─ Humidity is the amount of moisture in the air. Heat loss by
evaporation is hindered by high humidity but helped by low
humidity. As humidity rises, sweat tends to evaporate less. As a
result, body cooling decreases and body temperature increases
• Air Movement
─ Air movement affects the exchange of heat between the body and
the environment. As long as the air temperature is less than your
skin temperature, increasing air speed can help you stay cooler by
increasing both the rate of evaporation and the heat exchange
between the skin surface and the surrounding air.
Putting the
Factors
Together
While we can identify the Personal Risk Factors and the
Work Factor; the question comes up with combining
the Environmental Factors.
Have no fear….. There is a way to assess the
Environmental Factors. It is the:
Wet-Bulb Globe Temperature Index (WBGTI)
WBGTI
The Wet-Bulb Globe Temperature Index (WBGTI) takes
into account four variables:
•Air Temperature
•Humidity
•Radiant Heat
•Air Movement
This reading gives a more accurate measurement of heat
stress than any one reading alone.
• On the next slide you will see a “Fluid Replacement
and Work/Rest Guide/Chart”
• You will notice that the chart takes into consideration
the WBGTI reading as well as the type of work you are
doing and gives a “Heat Category”
Fluid Replacement and
Work/Rest Guide
Easy Wor k
Moder at e Wor k
H ar d Wor k
Heat
Category
WBGT
Index,
(F°)
Work/
Rest
Water
Intake
(Qt/h)
Work/
Rest
Water
Intake
(Qt/h)
Work/
Rest
Water
Intake
(Qt/h)
1
78-81.9
NL
½
NL
¾
40/20 min
¾
2
82-84.9
NL
½
50/10 min
¾
30/30 min
1
85-87.9
NL
¾
40/20 min
¾
30/30 min
1
4
(Red)
88-89.9
NL
¾
30/30 min
¾
20/40 min
1
5
> 90
50/10 min
1
20/40 min
1
10/50 min
1
(Green)
3
(Yellow)
(Black)
Easy Work = Walking hard surface 2.5 mph <30# load
Moderate Work = Patrolling, Walking sand 2.5 mph no load, Calisthenics
Hard Work = Walking sand 2.5 mph w/load
Using the: Fluid Replacement
and Work/Rest Guide
• In Civil Air Patrol they will tell you what the Heat Category is (ex:
1,2,3,4 or 5) or they will tell you what flag condition you are
under (ex: white, green, yellow, red or black). The Heat
Category is based on the WBGTI.
• Depending your work load and the Heat Category, you will be
able to note your work/rest time & fluid intake.
• Example: Red Flag & you are doing moderate work … You
need to work 30 minutes and then rest 30 min. You also need to
ensure you are drinking at least 3/4 quart of water every hour.
• Note: When you see “NL” on the chart it means “No Limit”
TYPES OF
HEAT INJURIES
There are three major types of heat injuries:
─ HEAT CRAMPS (caused by loss of salt)
─ HEAT EXHAUSTION (caused by dehydration)
─ HEAT STROKE (shock).
HEAT CRAMPS
Causes
Heat Cramps are usually the first stage of heat streess. Heat
Cramps are the result of dehydration and loss of electrolytes in body tissue.
This normally happens after exercise. Most often to people who aren’t used to
the heat, who sweat a lot or don’t drink enough fluids.
Symptoms
• Severe muscle cramps, usually in the legs and abdomen
• General weakness
• Sometimes dizziness or faintness
Treatment
•
•
•
•
•
Move the patient to a cool, shady place
Increase fluid intake (salted water or electrolytes --- Gatorade)
Massage & apply slight pressure to cramped area
Use moist towels on forehead and cramped muscle
Immediately transport to medical care facility if symptoms worsen
HEAT EXHAUSTION
Causes
Heat Exhaustion is the 2nd phase of heat
stress (although some individuals may never develop
heat cramps before going into heat exhaustion). This is
caused by the loss of body fluids and important salts
due to overexposure to high temperatures and
humidity. Usually you are exposed to heat for a
prolonged amount of time and you become dehydrated.
Symptoms
•
•
•
•
•
Treatment
•
•
•
•
•
•
Rapid & shallow breathing
Weak pulse
Cold & clammy skin
Heavy perspiration
Weakness/dizziness that may lead to unconsciousness
Move patient to cool, shady place & keep him/her at rest
Remove/loosen clothing to cool (not chill) the patient
Fan skin to promote sweat evaporation
If conscious provide salted water or a commercial electrolyte --- i.e. Gatorade.
Treat for shock and transport to a medical care facility
If left untreated Heat Exhaustion can lead to HEATSTROKE.
HEAT STROKE
Causes Heat stroke is the final phase of heat stress.
It is a life
threatening condition. It is the result of the body’s absolute
failure to regulate heat, and as a result the bodies core
temperature starts to rise (hyperthermia). This leads to the rapid
destruction of body tissues and brain cells. Permanent brain
damage and death are posible outcomes of Heat Stroke. Even if
successfully treated, it will take days for the patient to recover.
Symptoms
•
•
•
•
•
Deep breathing becoming progressively shallower.
A rapid, strong pulse becoming weaker.
Dry and hot skin
Dilated pupils.
Possible unconsciousness, seizures, and muscular twitching.
Treatment
• Remove the person from any heat sources and remove clothing
• If possible immerse patient in cool water, or use cold wet towel or ice packs in
the patient’s armpits, groin, under neck and behind knees. The key is to cool
the patient a rapidly as possible.
• TREAT FOR SHOCK AND TRANSPORT TO MEDICAL CARE IMMEDIATELY.
• DO NOT give medication to lower fever, DO NOT use an alcohol rub.
HEAT STROKE
Step One
Evaluate for heat stroke
If you suspect heat stroke, treat as follows:
.
Step Two
Move the patient out of direct sunlight,
preferably into a cool, shaded area
Step Three
Have the patient lie flat and elevate his or her feet.
Step Four
Remove heat-retaining clothing
Step Five
Wet the patient down and fan him or her,
or immerse the patient in cool water.
Step Six
Place ice packs on the patient's head,
back of the neck, armpits, palms of the hands,
soles of the feet and groin.
Step Seven
Hydrate well with lots of water, a diluted sports drink
or oral rehydration solution, but only if the patient is
conscious enough to hold a cup and drink
unassisted.
Step Eight
Monitor body temperature frequently:
• Keep careful notes on how long the patient remains at a
given temperature.
• Transfer these notes when you transfer care.
Step Nine
• Evacuate immediately
• Continue monitoring and writing down the patient's body
temperature.
SUMMARY
By now you should be able to take steps to
prevent hot weather injuries and recognize
and treat those that do occur.
Please click here to begin your
online review questions
This concludes the training for
this task.
More resources are available
on the SWR ES Training
Website.